I found this to be pretty efficient at cooling my small, Brooklyn apt bedroom. It even managed to keep the rest of the apartment bearable all by itself, though I did opt for a second unit to keep electricity down.

I personally appreciate the hum (I used to use a white noise machine before this A/C unit), but be aware that the unit is quite loud for the bedroom and could annoy/be an issue for some folks. I personally wish it was a bit quieter for the day time so I didn't have to wear headphones to hear music/watch shows.